From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 73D4C29AAF3 for ; Fri, 5 Jun 2026 18:51:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780685515; cv=none; b=EXdHXOoOnvNMEh7vjJsSLV2bxzlzyg/tZTROA7ahTV6yAg6BIbWyJoaabgJrk/o0Z1InkIKQAn5709bGBedU3XkTPxLe+YIon4pnbhws9kmaHe/rb0ad3f396w5j1EgcplyMw4Kayi28BaNOovJnCXleinFzUgFdBC93qK2NWKY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780685515; c=relaxed/simple; bh=WwyzoUFGghEi4lwn9ar9eD5MS67tyqWtpTaGMQuQSu4=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=hRUUsHLKWEIAnwUy5jRAti33AOymGJDe6y5fW2sTbDWt2B6ZYvJV2cYyIT1gf6vhWyUadeOE4sBqyJvdhcG3+lhnaYQNxnHXcECiv0DoK2CxQW5xaelql7srQ5a1xVzRfytBekyCoZSpZIfNYCCrq6I2Qgb/s2nphUWjlrr+4yw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=GnEwSK7g; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GnEwSK7g" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780685511; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=E/8+/pf30WAbPBX0MSXVhri10fbYoRgaJ6KeAOF/Zuk=; b=GnEwSK7g9HuJYZ2tFsLNLCt3XetUUe7KvVWw3AU4dfdAU5RS0/jcK6xeOTIKm/AWCagI80 TUvD2Od+xUpf0SVAYsOopKMwfEkcLG3A1zYBTV46YRoel3zJvSxY8m+xUJ6KjJ5f426kLA 4+wCl6CYM+t3iZ8CGVLksmuT11IwJqI= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-209-ODwdrsXXPEyB01Z8MrXazQ-1; Fri, 05 Jun 2026 14:51:48 -0400 X-MC-Unique: ODwdrsXXPEyB01Z8MrXazQ-1 X-Mimecast-MFC-AGG-ID: ODwdrsXXPEyB01Z8MrXazQ_1780685506 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4CC5D1956052; Fri, 5 Jun 2026 18:51:46 +0000 (UTC) Received: from RHTRH0061144 (unknown [10.22.88.184]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3DE233000210; Fri, 5 Jun 2026 18:51:44 +0000 (UTC) From: Aaron Conole To: Minxi Hou Cc: echaudro@redhat.com, i.maximets@ovn.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, shuah@kernel.org, netdev@vger.kernel.org, dev@openvswitch.org, linux-kselftest@vger.kernel.org, amorenoz@redhat.com Subject: Re: [PATCH net-next] selftests/net/openvswitch: add flow modify test In-Reply-To: <20260605124222.963815-1-houminxi@gmail.com> (Minxi Hou's message of "Fri, 5 Jun 2026 20:42:22 +0800") References: <20260605124222.963815-1-houminxi@gmail.com> Date: Fri, 05 Jun 2026 14:51:43 -0400 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Minxi Hou writes: > Add mod_flow() and the mod-flow CLI command to ovs-dpctl.py, exercising > OVS_FLOW_CMD_SET. Add test_flow_set which first modifies an existing > flow with new actions and verifies the change via traffic, then modifies > the same flow without actions and verifies the kernel handles the > no-actions case gracefully. > > The no-actions path is unreachable from userspace OVS tools (dpctl > mod-flow requires actions) but reachable via raw netlink. This is the > code path where Adrian Moreno found a possible kfree_skb of ERR_PTR > when reply allocation fails after locking. > > Make parse() skip OVS_FLOW_ATTR_ACTIONS when actstr is None so the > kernel enters the post-lock allocation branch in ovs_flow_cmd_set(). > > Suggested-by: Aaron Conole > Signed-off-by: Minxi Hou > --- Thanks for the really quick turnaround. I'll do a deeper review of the code on Monday; I wanted to reply though because I was expecting to see a splat in the selftest, but instead it passed. This confused me at first, because I didn't realize that the net- targeted patches were also applied in the net-next test run: https://github.com/linux-netdev/testing/commit/30e78e3cb99d9abb5182c387abdf5ede29fb9589 ("net: openvswitch: fix possible kfree_skb of ERR_PTR") But we will want to make sure that whenever this selftest would finally get applied the above kfree_skb fix is also applied. > .../selftests/net/openvswitch/openvswitch.sh | 72 +++++++++++++++++++ > .../selftests/net/openvswitch/ovs-dpctl.py | 39 +++++++++- > 2 files changed, 108 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh b/tools/testing/selftests/net/openvswitch/openvswitch.sh > index a415e9dec8cd..71190bc662f9 100755 > --- a/tools/testing/selftests/net/openvswitch/openvswitch.sh > +++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh > @@ -30,6 +30,7 @@ tests=" > drop_reason drop: test drop reasons are emitted > pop_vlan vlan: POP_VLAN action strips tag > dec_ttl ttl: dec_ttl decrements IP TTL > + flow_set flow-set: Flow modify > psample psample: Sampling packets with psample" > > info() { > @@ -193,6 +194,23 @@ ovs_add_flow () { > return 0 > } > > +ovs_mod_flow () { > + if [ -n "$4" ]; then > + info "Modifying flow: sbx:$1 br:$2 flow:$3 act:$4" > + ovs_sbx "$1" python3 $ovs_base/ovs-dpctl.py \ > + mod-flow "$2" "$3" "$4" > + else > + info "Modifying flow (no actions): sbx:$1 br:$2 flow:$3" > + ovs_sbx "$1" python3 $ovs_base/ovs-dpctl.py \ > + mod-flow "$2" "$3" > + fi > + if [ $? -ne 0 ]; then > + info "Flow modify [ $3 ] failed" > + return 1 > + fi > + return 0 > +} > + > ovs_del_flows () { > info "Deleting all flows from DP: sbx:$1 br:$2" > ovs_sbx "$1" python3 $ovs_base/ovs-dpctl.py del-flows "$2" > @@ -300,6 +318,60 @@ test_dec_ttl() { > return 0 > } > > +test_flow_set() { > + sbx_add "test_flow_set" || return $? > + ovs_add_dp "test_flow_set" flowset || return 1 > + > + info "create namespaces" > + for ns in client server; do > + ovs_add_netns_and_veths "test_flow_set" "flowset" "$ns" \ > + "${ns:0:1}0" "${ns:0:1}1" || return 1 > + done > + > + ip netns exec client ip addr add 10.0.0.1/24 dev c1 > + ip netns exec client ip link set c1 up > + ip netns exec server ip addr add 10.0.0.2/24 dev s1 > + ip netns exec server ip link set s1 up > + > + ovs_add_flow "test_flow_set" flowset \ > + 'in_port(1),eth(),eth_type(0x0806),arp()' '2' || return 1 > + ovs_add_flow "test_flow_set" flowset \ > + 'in_port(2),eth(),eth_type(0x0806),arp()' '1' || return 1 > + > + local fwd_flow="ufid:00000001-0002-0003-0004-000500060007" > + fwd_flow="$fwd_flow,in_port(1),eth(),eth_type(0x0800),ipv4()" > + > + ovs_add_flow "test_flow_set" flowset "$fwd_flow" '2' \ > + || return 1 > + ovs_add_flow "test_flow_set" flowset \ > + 'in_port(2),eth(),eth_type(0x0800),ipv4()' '1' || return 1 > + > + info "verify initial forwarding" > + ovs_sbx "test_flow_set" ip netns exec client ping -c 1 -W 2 \ > + 10.0.0.2 || return 1 > + > + info "mod-flow with new actions (change to drop)" > + ovs_mod_flow "test_flow_set" flowset "$fwd_flow" 'drop' \ > + || return 1 > + > + info "verify traffic is now dropped" > + ovs_sbx "test_flow_set" ip netns exec client ping -c 1 -W 2 \ > + 10.0.0.2 >/dev/null 2>&1 \ > + && { info "FAIL: ping should fail after mod-flow to drop" > + return 1; } > + > + info "mod-flow without actions" > + ovs_mod_flow "test_flow_set" flowset "$fwd_flow" || return 1 > + > + info "verify drop actions unchanged" > + ovs_sbx "test_flow_set" ip netns exec client ping -c 1 -W 2 \ > + 10.0.0.2 >/dev/null 2>&1 \ > + && { info "FAIL: ping should still fail after no-actions set" > + return 1; } > + > + return 0 > +} > + > # psample test > # - use psample to observe packets > test_psample() { > diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py > index 3342e295293d..9113473d425f 100644 > --- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py > +++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py > @@ -2702,9 +2702,10 @@ class OvsFlow(GenericNetlinkSocket): > self["attrs"].append(["OVS_FLOW_ATTR_KEY", k]) > self["attrs"].append(["OVS_FLOW_ATTR_MASK", m]) > > - a = ovsactions() > - a.parse(actstr) > - self["attrs"].append(["OVS_FLOW_ATTR_ACTIONS", a]) > + if actstr is not None: > + a = ovsactions() > + a.parse(actstr) > + self["attrs"].append(["OVS_FLOW_ATTR_ACTIONS", a]) > > def __init__(self): > GenericNetlinkSocket.__init__(self) > @@ -2738,6 +2739,24 @@ class OvsFlow(GenericNetlinkSocket): > raise ne > return reply > > + def mod_flow(self, dpifindex, flowmsg): > + flowmsg["cmd"] = OVS_FLOW_CMD_SET > + flowmsg["version"] = OVS_DATAPATH_VERSION > + flowmsg["reserved"] = 0 > + flowmsg["dpifindex"] = dpifindex > + > + try: > + reply = self.nlm_request( > + flowmsg, > + msg_type=self.prid, > + msg_flags=NLM_F_REQUEST | NLM_F_ACK, > + ) > + reply = reply[0] > + except NetlinkError as ne: > + print(flowmsg) > + raise ne > + return reply > + > def del_flows(self, dpifindex): > """ > Send a del message to the kernel that will drop all flows. > @@ -3013,6 +3032,12 @@ def main(argv): > addflcmd.add_argument("flow", help="Flow specification") > addflcmd.add_argument("acts", help="Flow actions") > > + modflcmd = subparsers.add_parser("mod-flow") > + modflcmd.add_argument("modbr", help="Datapath name") > + modflcmd.add_argument("modflow", help="Flow specification") > + modflcmd.add_argument("modacts", help="Flow actions", > + nargs="?", default=None) > + > delfscmd = subparsers.add_parser("del-flows") > delfscmd.add_argument("flsbr", help="Datapath name") > > @@ -3110,6 +3135,14 @@ def main(argv): > flow = OvsFlow.ovs_flow_msg() > flow.parse(args.flow, args.acts, rep["dpifindex"]) > ovsflow.add_flow(rep["dpifindex"], flow) > + elif hasattr(args, "modbr"): > + rep = ovsdp.info(args.modbr, 0) > + if rep is None: > + print("DP '%s' not found." % args.modbr) > + return 1 > + flow = OvsFlow.ovs_flow_msg() > + flow.parse(args.modflow, args.modacts, rep["dpifindex"]) > + ovsflow.mod_flow(rep["dpifindex"], flow) > elif hasattr(args, "flsbr"): > rep = ovsdp.info(args.flsbr, 0) > if rep is None: